The Lega (League) leader, who has surged in popularity since coming to office as head of one half of Italy’s new populist coalition government, made the comments in an interview on the In Onda television programme.

Salvini accused the convicted insider trader of financing the so-called civil society NGOs which have been racing the Libyan Coast Guard to pick up illegal migrants from smuggler boats a few miles off the North African coast, in order to ferry them to distant European ports.

“Soros wants to fill Italy and Europe with migrants,” Salvini told La7 TV viewers, adding that he “would like Italy [to become] a giant refugee camp because he likes slaves”.

The populist later shared the comments on his social media, so they could be seen by an even wider audience.

Open Society Foundations, Soros’s flagship NGO into which he recently poured 18 billion dollars, has now issued a furious denial, demanding Salvini stop “repeating these and similar false statements about Mr Soros”.

Salvini has challenged the financier and his foundation before, claiming the NGO and its partners have made it their business to promote uncontrolled immigration, liberalisation of drug use, and social policies which undermine the family and promote alternative lifestyles and gender identities.

“So no more families with a Mum and Dad. Isn’t it way better to have an ‘open society’ with six dads, three mums, 18 great-grandparents, and six cousins, who also change gender according to the mood of the day? … And sometimes they smoke pot together!” he quipped sarcastically.

“This is the project they want to leave to our children. Why? Because then you no longer have a man or a woman — you have a number, an item, with no rights, no history, no thought, no nationality, no identity… They are very well organised enemies, and they are very rich,” he warned.

“But we’ll prevail. Because history tells us that when peoples wake up and realise that they are in danger, they react.”